Metering oven

Abstract

The invention concerns a metering oven ( 1 ) with a vessel ( 12 ) for holding a liquid metal and with a device for detecting a liquid metal level in a vessel. A tubular probe ( 5 ) is connected to a gas source ( 10 ) for discharging a gas at a predetermined pressure from the gas source through the probe and out of its aperture. The probe is spatially associated in a fixed manner with the vessel such that pressures which can be detected by a pressure-measuring device ( 9 ) can be associated with different liquid metal levels inside the probe. At a given pressure threshold value, the pressure-measuring device can emit a signal for a given liquid metal level to be detected.

What is claimed is:  
     
       1. Metering oven ( 1 ) with a vessel ( 12 ) for receiving liquid metal and a device for detecting a level of liquid metal in a vessel, a tubular probe ( 5 ) being connected to a gas source ( 10 ) for discharging a gas from the gas source through the probe and out of its outlet aperture, and a pressure measuring device ( 9 ) being provided for detecting a state of pressure inside the probe ( 5 ) in dependence on a counter-pressure caused by a level of the liquid metal, wherein the pressure measuring device ( 9 ) is a pressure wave switch for detecting a pressure response occurring inside the probe ( 5 ) when the probe opening is blocked by liquid metal and to emit a corresponding signal, and in that the probe ( 5 ) is securely inserted into the wall of an ascending pipe ( 3 ) provided in the vessel ( 12 ). 
     
     
       2. Metering oven according to claim  1 , wherein the probe or the ascending pipe ( 3 ) consist of ceramics or substantially of ceramics. 
     
     
       3. Metering oven according to claim  1 , wherein the probe ( 5 ) is pressed or glued into a bore ( 8 ). 
     
     
       4. Metering oven according to claim  3 , wherein the outlet aperture of the probe ( 5 ) or the bore ( 8 ) has an inner diameter of less than 5 mm. 
     
     
       5. Metering oven according to claim  1 , wherein the pressure wave switch may be adjusted in pressure sensitivity. 
     
     
       6. Metering oven according to claim  1 , wherein a first and a second device for detecting a level of liquid metal are provided, which have a first and a second probe with a first and a second outlet aperture. 
     
     
       7. Metering oven according to claim  6 , wherein the first outlet aperture lies, with respect to a static level of the liquid metal, above or near the second outlet aperture.